PD-1 and PD-L1 as emerging therapeutic targets in gastric cancer: current evidence

Assessing clinical pathological characteristics and gene expression patterns associated with hepatoid adenocarcinoma of the stomach

OBJECTIVE

The objective of this study is to assess the clinical pathological attributes of Hepatoid Adenocarcinoma of the Stomach (HAS) and to delineate the differential diagnostic considerations about it.

METHOD

The investigation involved analyzing 31 HAS cases using histomorphological assessment, immunohistochemical profiling, and relevant gene detection methodologies.

RESULTS

Among the 31 HAS cases, 9 (29.0%) were of trabecular hepatoid adenocarcinoma of the stomach, 7 (22.6%) were of glandular hepatoid adenocarcinoma of the stomach, 4 (12.9%) were of nesting hepatoid adenocarcinoma of the stomach, 3 (9.7%) were of clear cell hepatoid adenocarcinoma of the stomach, and 8 (25.8%) were of diverse hepatoid adenocarcinoma of the stomach. Of these 31 cases, 24 were male, accounting for 77.4% of the cases. Serum alpha-fetoprotein (AFP) levels were notably elevated, with radioimmunoassay results reaching 1240 ng/ml; 28 out of 31 cases had AFP levels below 25 µg/l, accounting for 90.3%. Related genes: HER2 protein indicated positive expression on the cell membrane in 35.5% (11/31) of the cases; HER2 gene amplification detected by the FISH technique was 12.9% (4/31). Tumoral stromal lymphocytes exhibited a PD-1 positive expression rate of 58.1% (18/31). In gastric cancer tissues, the PD-L1 positive rate was 45.1% (14/31).

CONCLUSION

HAS represents a distinctive subtype of gastric cancer with a propensity for mimicking other forms of tumors, underscoring the significance of discerning its unique histopathological attributes for accurate differential diagnosis and tailored therapeutic interventions.

Clinicopathological features and differential diagnosis of gastric pleomorphic giant cell carcinoma

The aim of this study was to investigate the clinicopathological features and differential diagnosis of gastric pleomorphic giant cell carcinoma. Histopathology, immunohistochemistry, and human epidermal growth factor receptor 2 (HER2) gene testing were conducted for seven cases of gastric pleomorphic giant cell carcinoma. In histomorphological terms, all seven cases involved pleomorphic giant cell carcinoma, accounting for more than 10% of the entire tumor, with pleomorphic spindle cells and giant cells mixed with various histomorphological structures of adenocarcinoma with high, intermediate, and low differentiation. There was large heterogeneity in the HER2 protein expression and HER2 gene amplification in the gastric pleomorphic giant cell carcinoma, and both levels of HER2 were focal in three cases, accounting for 42.9% (3/7). The mismatch repair gene proteins MLH1, MSH2, PMS2, and MSH6 were positive. Routine immunohistochemical markers, i.e., pan-cytokeratin, epithelial membrane antigen, villin, caudal-type homeobox 2, E-cadherin, and p53, were positive in the gastric pleomorphic giant cell carcinoma, while vimentin, calponin, smooth muscle actin, nestin, S-100, cluster of differentiation (CD) 99, desmin, and CD34 were focally expressed in both the spindle and the giant cells, with Ki-67-positive cells accounting for 70-80%. Gastric pleomorphic giant cell carcinoma presents multiple histomorphological features and is easily confused with various tumors. Clarifying the histopathological features of this type of tumor is important for differential diagnosis and precise treatment.

Identification of RFX5 as prognostic biomarker and associated with immune infiltration in stomach adenocarcinoma

Background

Regulatory factor X (RFX) gene family is a series of encodes transcription factors with a highly conserved DNA binding domain. RFXs played a vital role in the development and progression of cancer. However, the significance of RFXs in stomach adenocarcinoma (STAD) has not been fully clarified.

Methods

Online bioinformatics tools such as GSCALite, Kaplan–Meier Plotter, TIMER, LinkedOmics were used to explore the immunomodulatory function and clinical value of RFXs in STAD.

Results

The mRNA level of RFX1, RFX3, RFX4, RFX5, RFX7 and RFX8 was significantly elevated in STAD tissue versus adjacent normal tissue. We also summarize the copy number variation, single nucleotide variants and drug sensitivity of RFXs in STAD. Prognostic analysis indicated that STAD patients with high RFX5 and RFX7 expression had a better overall survival, first progression, and post-progression survival. Moreover, RFX5 expression was significantly associated with the abundance of immune cells, the expression of immune biomarkers and tumor mutational burden score in STAD. Functional enrichment analysis revealed that RFX5 and its related genes were mainly involved in T cell activation, antigen receptor-mediated signaling pathway, cell adhesion molecules, and Th17 cell differentiation. Validation study further verified the expression and prognosis of RFX5 in STAD. Further univariate and multivariate analyses suggested that pathological stage and RFX5 could be a potential independent prognostic factor for STAD.

Conclusions

RFX5 was a candidate prognostic biomarker and associated with immune infiltration in STAD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40001-022-00794-w.

Tumor vessel normalization and immunotherapy in gastric cancer

Gastric cancer (GC) is a common malignant tumor, and patients with GC have a low survival rate due to limited effective treatment methods. Angiogenesis and immune evasion are two key processes in GC progression, and they act synergistically to promote tumor progression. Tumor vascular normalization has been shown to improve the efficacy of cancer immunotherapy, which in turn may be improved through enhanced immune stimulation. Therefore, it may be interesting to identify synergies between immunomodulatory agents and anti-angiogenic therapies in GC. This strategy aims to normalize the tumor microenvironment through the action of the anti-vascular endothelial growth factor while stimulating the immune response through immunotherapy and prolonging the survival of GC patients.

Identification and Validation of Immune Cells and Hub Genes in Gastric Cancer Microenvironment

Gastric cancer (GC) is the most common malignant tumor in the digestive system, traditional radiotherapy and chemotherapy are not effective for some patients. The research progress of immunotherapy seems to provide a new way for treatment. However, it is still urgent to predict immunotherapy biomarkers and determine novel therapeutic targets. In this study, the gene expression profiles and clinical data of 407 stomach adenocarcinoma (STAD) patients were downloaded from The Cancer Genome Atlas (TCGA) portal, and the abundance ratio of immune cells in each sample was obtained via the “Cell Type Identification by Estimating Relative Subsets of RNA Transcripts (CIBERSORT)” algorithm. Five immune cells were obtained as a result of abundance comparison, and 295 immune-related genes were obtained through differential gene analysis. Enrichment, protein interaction, and module analysis were performed on these genes. We identified five immune cells associated with infiltration and 20 hub genes, of which five genes were correlated with overall survival. Finally, we used Real-time PCR (RT-PCR) to detect the expression differences of the five hub genes in 18 pairs of GC and adjacent tissues. This research not only provides cellular and gene targets for immunotherapy of GC but also provides new ideas for researchers to explore immunotherapy for various tumors.

Negative Correlation Between 18F-RGD Uptake via PET and Tumoral PD-L1 Expression in Non-Small Cell Lung Cancer

PURPOSE

We investigated the correlation of ¹⁸F-AlF-NOTAPRGD2 (¹⁸F-RGD) uptake during positron emission tomography (PET) with tumoral programmed death-ligand 1 (PD-L1) expression and explored its potential in immune checkpoint inhibitor treatment.

METHODS

Forty-two mice were subcutaneously injected with CMT-167 lung carcinoma cells. A total of 30 mice with good growth tumor and good general condition were selected. ¹⁸F-RGD PET scanning was performed on days 0, 2, 4, 6, 9, and 11 with five mice per day. Immunohistochemistry (IHC) for PD-L1 was performed on each specimen obtained from tumors. Thirty patients with advanced non-small cell lung cancer (NSCLC) were scanned using ¹⁸F-RGD PET/CT, and Milliplex multifactor detection analyzed serum PD-1/PD-L1 expression of twenty-eight of them. Thirteen of them were analyzed immunohistochemically using core needle biopsy samples obtained from primary tumors.

RESULTS

Thirty mice were scanned by ¹⁸F-RGD PET/CT and analyzed for PD-L1 expression in tumor cells by IHC finally. Maximum standard uptake value (SUVmax) and mean SUV (SUVmean) were significantly lower in relatively-higher-PD-L1-expression tumors than in relatively-low-PD-L1-expression tumors (P < 0.05). In patients, the SUVmax was significantly negatively correlated with tumoral PD-L1 expression by IHC (P=0.014). SUVmean, peak SUV (SUVpeak), and gross tumor volume (GTV) were also negatively correlated with PD-L1, but without significance (P > 0.05). SUVmax, SUVmean, SUVpeak, and GTV were negatively correlated with serum PD-1 and PD-L1, but not significantly. According to the receiver operating characteristic curve analysis, significant correlations between SUVmax and tumoral PD-L1 expression in both mice and patients were present (P < 0.05).

CONCLUSION

Higher ¹⁸F-RGD uptake is correlated with depressed PD-L1 expression in tumor cells, and SUVmax is the best parameter to display tumoral expression of PD-L1. ¹⁸F-RGD PET may be useful for reflecting the immune status of NSCLC.

Genome Instability-Related miRNAs Predict Survival, Immune Landscape, and Immunotherapy Responses in Gastric Cancer

BACKGROUND

Increasing evidence suggests that microRNAs (miRNAs) are involved in genome instability (GI) and drive the occurrence of tumors. However, the role of GI-related miRNAs in gastric cancer (GC) remains largely unknown. Herein, we developed a novel GI-related miRNA signature (GIMiSig) and further investigated its role in prognosis, the immune landscape, and immunotherapy responses in GC patients.

METHODS

An analysis of somatic mutation data on 434 gastric cancer cases from The Cancer Genome Atlas (TCGA) database was performed, thereby generating genome stability (GS) and GI groups. By detecting differentially expressed miRNAs between the GS and GI groups that were associated with overall survival, 8 miRNAs were identified and used to construct the GIMiSig.

RESULTS

The GIMiSig showed high accuracy in detecting GC patients. Using GIMiSig to stratify the patients into the high- and low-risk subgroups to predict survival outperformed the use of regular clinical features such as age, gender, or disease stage. Patients with low risk had a more favorable survival time than those with high risk. More importantly, the high-risk patients were associated with decreased UBQLN4 expression, higher accumulation of immune cells, lower Titin (TTN) mutation frequency, worse immunotherapy efficacy, and cancer-associated pathways. Conversely, the low-risk patients were characterized by UBQLN4 overexpression, lower fraction of immune cells, higher TTN mutation frequency, better response to immunotherapy, and GI-related pathways.

CONCLUSION

In summary, we constructed a novel GIMiSig that could stratify GC patients into distinct risk groups that have different survival outcomes and immunotherapy efficacy. The results may provide new clues for improving GC outcomes.

Chemoradiation induces upregulation of immunogenic cell death-related molecules together with increased expression of PD-L1 and galectin-9 in gastric cancer

Surgery alone or combined with chemo- and/or radiation therapy remains the primary treatment for gastric cancer (GC) to date and immunotherapeutic tools such as monoclonal antibodies are only slowly being implemented. This is partly due to the fact that the immune microenvironment in GC during chemoradiation and other treatment modalities is still poorly understood. 7 gastric cancer (GC) cell lines were tested for their response to chemoradiation using 5-FU in combination with X-ray irradiation. We conducted flow cytometric analysis to determine the cells’ ability to undergo immunogenic cell death (ICD) and their expression of the two immunosuppressive proteins programmed death-ligand 1 (PD-L1) and galectin-9 (Gal-9). We evaluated the overall immunogenicity of two cell lines (MKN7, MKN74) in co-culture experiments with human monocyte-derived dendritic cells (Mo-DCs). Chemoradiation induces distinct responses in different GC cell lines. We observe ICD in vitro in all tested GC cell lines in the form of calreticulin (CRT) translocation to the plasma membrane. As a resistance mechanism, these cells also upregulated Gal-9 and PD-L1. Mo-DC maturation experiments showed that GCs provoked the maturation of Mo-DCs after chemoradiation in vitro. The addition of α-PD-L1 blocking antibody further enhanced the immunogenicity of these cells while improving DC viability. Blocking Tim-3, as the main receptor for Gal-9, had no such effect. Our findings suggest that the benefits of chemoradiation can substantially depend on tumor subtype and these benefits can be offset by induced immune evasion in GC. Combination treatment using checkpoint inhibitors could potentially lead to enhanced immune responses and yield better patient outcomes.

Tislelizumab in Chinese patients with advanced solid tumors: an open-label, non-comparative, phase 1/2 study

BACKGROUND

Tislelizumab is an investigational, humanized, IgG4 monoclonal antibody with high affinity and binding specificity for programmed cell death-1 (PD-1) that was engineered to minimize binding to FcγR on macrophages in order to abrogate antibody-dependent phagocytosis, a mechanism of T-cell clearance and potential resistance to anti-PD-1 therapy.

METHODS

The purpose of this phase 1/2, open-label, non-comparative study was to examine the safety, tolerability, and antitumor activity of tislelizumab in adult (≥18 years) Chinese patients with histologically or cytologically confirmed advanced solid tumors with measurable disease. The phase 1 portion of the study consisted of a dose-verification study and a pharmacokinetic (PK) substudy; phase 2 was an indication-expansion study including 11 solid tumor cohorts. Patients previously treated with therapies targeting PD-1 or its ligand, programmed cell death ligand-1 were excluded. During dose-verification, dose-limiting toxicities (DLTs) were monitored; safety and tolerability were examined and the previously determined recommended phase 2 dose (RP2D) was verified. The primary endpoint of phase 2 was investigator-assessed objective response rate per Response Evaluation Criteria in Solid Tumors V.1.1.

RESULTS

As of December 1, 2018, 300 patients were treated with tislelizumab 200 mg intravenously once every 3 weeks (Q3W). Median duration of follow-up was 8.1 months (range 0.2-21.9). No DLTs were reported during the phase 1 dose-verification study and the RP2D was confirmed to be 200 mg intravenously Q3W. Most treatment-related adverse events (62%) were grade 1 or 2, with the most common being anemia (n=70; 23%) and increased aspartate aminotransferase (n=67; 22%). Of the 251 efficacy evaluable patients, 45 (18%) achieved a confirmed clinical response, including one patient from the PK substudy who achieved a complete response. Median duration of response was not reached for all except the nasopharyngeal carcinoma cohort (8.3 months). Antitumor responses were observed in multiple tumor types.

CONCLUSIONS

Tislelizumab was generally well tolerated among Chinese patients. Antitumor activity was observed in patients with multiple solid tumors.

TRIAL REGISTRATION NUMBER

CTR20160872.

Expression of the immune checkpoint molecule V-set immunoglobulin domain-containing 4 is associated with poor prognosis in patients with advanced gastric cancer

BACKGROUND

Recent clinical studies on immune checkpoint (IC) inhibitors in the context of advanced gastric cancer (AGC) have failed to show significant survival benefits but have suggested the possible role of IC inhibitors in anti-AGC immunity. Considering the low efficacy of targeted drugs in AGC, there is an urgent need for the discovery of new targets for the development of immunotherapeutics and prognostic markers for patient selection. This study aimed to investigate the expression of a new IC molecule, V-set Ig domain-containing 4 (VSIG4), and its clinical significance in AGC and other major cancers.

METHODS

We analyzed the expression of VSIG4 and its correlation with survival in various carcinomas, including 882 surgically resected samples from patients with stage II-III AGC (two academic hospitals).

RESULTS

VSIG4 positivity in AGC was significantly associated with overall survival (OS; Hazard ratio (HR) = 2.661, 95% confidence interval [CI] = 2.012-3.519, P < 0.001) and event-free survival (HR = 2.8, 95% CI = 2.18-3.72, P < 0.001). These findings were successfully validated in independent cohorts. VSIG4 expression was also significantly correlated with low intratumoral CD8 + T-cell infiltration (CD8i) (P = 0.029) and high Foxp3 + /CD8i ratio (P = 0.026), which is consistent with the previously reported immunological function of VSIG4. However, VSIG4 expression was not associated with survival in other cancers (colon, P = 0.459; lung, P = 0.275; kidney, P = 0.121; breast, P = 0.147).

CONCLUSION

Our results suggest that VSIG4 is an independent prognostic factor in AGC and also implies that VSIG4 is a second-tier IC molecule in AGC, thus, providing an important basis for the development of gastric cancer-specific immunotherapeutics.

Mining The Cancer Genome Atlas database for tumor mutation burden and its clinical implications in gastric cancer

BACKGROUND

Tumor mutational burden (TMB) is an important independent biomarker for the response to immunotherapy in multiple cancers. However, the clinical implications of TMB in gastric cancer (GC) have not been fully elucidated.

AIM

To explore the landscape of mutation profiles and determine the correlation between TMB and microRNA (miRNA) expression in GC.

METHODS

Genomic, transcriptomic, and clinical data from The Cancer Genome Atlas were used to obtain mutational profiles and investigate the statistical correlation between mutational burden and the overall survival of GC patients. The difference in immune infiltration between high- and low-TMB subgroups was evaluated by Wilcoxon rank-sum test. Furthermore, miRNAs differentially expressed between the high- and low-TMB subgroups were identified and the least absolute shrinkage and selection operator method was employed to construct a miRNA-based signature for TMB prediction. The biological functions of the predictive miRNAs were identified with DIANA-miRPath v3.0.

RESULTS

C>T single nucleotide mutations exhibited the highest mutation incidence, and the top three mutated genes were TTN, TP53, and MUC16 in GC. High TMB values (top 20%) were markedly correlated with better survival outcome, and multivariable regression analysis indicated that TMB remained prognostic independent of TNM stage, histological grade, age, and gender. Different TMB levels exhibited different immune infiltration patterns. Significant differences between the high- and low-TMB subgroups were observed in the infiltration of CD8+ T cells, M1 macrophages, regulatory T cells, and CD4+ T cells. In addition, we developed a miRNA-based signature using 23 differentially expressed miRNAs to predict TMB values of GC patients. The predictive performance of the signature was confirmed in the testing and the whole set. Receiver operating characteristic curve analysis demonstrated the optimal performance of the signature. Finally, enrichment analysis demonstrated that the set of miRNAs was significantly enriched in many key cancer and immune-related pathways.

CONCLUSION

TMB

Metastatic Gastric cancer: Real world scenario from a developing country

Aim:

Data on epidemiology and outcome in metastatic stomach carcinoma patients from India are scarce. We aimed to evaluate clinical features and treatment outcome in patients treated at our center.

Materials and Methods:

This is a single institutional review of metastatic gastric carcinoma patients treated between May 2011 and October 2016. Patients who received at least one cycle of chemotherapy were included for modified intent-to-treat survival analysis.

Results:

total of 143 patients were diagnosed with metastatic stomach carcinoma with a median age of 56 years (range: 29–86). The most common symptoms were abdominal pain in 112 (78%) patients. The most common site was body in 81 (57%) patients. Common site of metastasis was peritoneum in 86 (60%) and liver in (62%). Seventy-one (50%) patients were eligible for survival analysis. Common chemotherapy regimens were capecitabine-cisplatin in 27 (38%) and EOX in 22 (31%) patients. Survival status could not be assessed in 29 (41%) patients who lost to follow-up. After a median follow-up 9.7 months (range: 0.5–37.7), median progression-free survival (PFS) was 7.9 months (range: 0.5–23.9) and median overall survival (OS) was 12.2 months (range: 0.5–37.7). The Eastern Cooperative Oncology Group (ECOG) performance status (PS) ≥2 and the presence of linitis plastica showed a trend toward inferior PFS (P = 0.052 and 0.053, respectively) only in univariate analysis. Female sex and ECOG PS ≥2 predicted inferior OS in both univariate and multivariate analysis (P = 0.012, 0.02 and 0.03 and 0.05, respectively).

Conclusions:

Platinum-based doublet chemotherapy was used in the majority of patients. The overall outcome was comparable to that of the available literature. Female sex and ECOG PS ≥2 predicted the inferior outcome.

Significance of Detection of the HER2 Gene and PD-1/PD-L1 in Gastric Cancer

Objective

To explore the relationship between the HER2 gene and PD-1/PD-L1 in gastric cancer and its significance.

Methods

Immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) were used to detect HER2 protein expression, HER2 gene amplification, and PD-1/PD-L1 expression in 78 cases of gastric cancer.

Results

The expression rate of HER2 protein was 43.6% (34/78), of which 19.4% (14/78) were HER2 3+, 14.1% (11/78) were HER2 2+, and 11.5% (9/78) were HER2 1+. The results showed that 19.2% (15/78) of samples had HER2 gene amplification, 3.8% (3/78) of samples had a HER2/CEP17 ratio <2.0, and 19.2% (15/78) of samples had HER2 gene amplificationf and HER2 copy/cell ≥6.0, as detected by FISH. The positive rate of PD-L1 was 38.5% (30/78) in gastric cancer cells and 50.0% (39/78) in interstitial lymphocytes. The expression of the HER2 gene, PD-L1, and PD-1 in gastric cancer was correlated with the stage and lymph node metastasis of gastric cancer (P < 0.05).

Conclusions

The combined detection of the HER2 gene and PD-1/PD-L1 in gastric cancer provides an important reference index for the prognosis of gastric cancer and the benefit of targeted antitumor drugs.

A Multi-Gene Model Effectively Predicts the Overall Prognosis of Stomach Adenocarcinomas With Large Genetic Heterogeneity Using Somatic Mutation Features

Background

Stomach adenocarcinoma (STAD) is one of the most common malignancies worldwide with poor prognosis. It remains unclear whether the prognosis is associated with somatic gene mutations.

Methods

In this research, we collected two independent STAD cohorts with both genetic profiling and clinical follow-up data, systematically investigated the association between the prognosis and somatic mutations, and analyzed the influence of heterogeneity on the prognosis-genetics association.

Results

Typical association was identified between somatic mutations and overall prognosis for individual cohorts. In The Cancer Genome Atlas (TCGA) cohort, a list of 24 genes was also identified that tended to mutate within cases of the poorest prognosis. The association showed apparent heterogeneity between different cohorts, although common signatures could be identified. A machine-learning model was trained with 20 common genes that showed a similar mutation rate difference between prognostic groups in the two cohorts, and it classified the cases in each cohort into two groups with significantly different prognosis. The model outperformed both single-gene models and TNM-based staging system significantly.

Conclusion

The study made a systematic analysis on the association between STAD prognosis and somatic mutations, identified signature genes that showed mutation preference in different prognostic groups, and developed an effective multi-gene model that can effectively predict the overall prognosis of STAD in different cohorts.

Computational analysis of morphological and molecular features in gastric cancer tissues

Biological morphologies of cells and tissues represent their physiological and pathological conditions. The importance of quantitative assessment of morphological information has been highly recognized in clinical diagnosis and therapeutic strategies. In this study, we used a supervised machine learning algorithm wndchrm to classify hematoxylin and eosin (H&E)‐stained images of human gastric cancer tissues. This analysis distinguished between noncancer and cancer tissues with different histological grades. We then classified the H&E‐stained images by expression levels of cancer‐associated nuclear ATF7IP/MCAF1 and membranous PD‐L1 proteins using immunohistochemistry of serial sections. Interestingly, classes with low and high expressions of each protein exhibited significant morphological dissimilarity in H&E images. These results indicated that morphological features in cancer tissues are correlated with expression of specific cancer‐associated proteins, suggesting the usefulness of biomolecular‐based morphological classification.

C1GALT1 is associated with poor survival and promotes soluble Ephrin A1-mediated cell migration through activation of EPHA2 in gastric cancer

C1GALT1 controls the crucial step of GalNAc-type O-glycosylation and is associated with both physiologic and pathologic conditions, including cancers. EPH receptors comprise the largest family of receptor tyrosine kinases (RTKs) and modulate a diverse range of developmental processes and human diseases. However, the role of C1GALT1 in the signaling of EPH receptors remains largely overlooked. Here, we showed that C1GALT1 high expression in gastric adenocarcinomas correlated with adverse clinicopathologic features and is an independent prognostic factor for poor overall survival. Silencing or loss of C1GALT1 inhibited cell viability, migration, invasion, tumor growth and metastasis, as well as increased apoptosis and cytotoxicity of 5-fluorouracil in AGS and MKN45 cells. Phospho-RTK array and western blot analysis showed that C1GALT1 depletion suppressed tyrosine phosphorylation of EPHA2 induced by soluble Ephrin A1-Fc. O-glycans on EPHA2 were modified by C1GALT1 and both S277A and T429A mutants, which are O-glycosites on EPHA2, dramatically enhanced phosphorylation of Y588, suggesting that not only overall O-glycan structures but also site-specific O-glycosylation can regulate EPHA2 activity. Furthermore, depletion of C1GALT1 decreased Ephrin A1-Fc induced migration and reduced Ephrin A1 binding to cell surfaces. The effects of C1GALT1 knockdown or knockout on cell invasiveness in vitro and in vivo were phenocopied by EPHA2 knockdown in gastric cancer cells. These results suggest that C1GALT1 promotes phosphorylation of EPHA2 and enhances soluble Ephrin A1-mediated migration primarily by modifying EPHA2 O-glycosylation. Our study highlights the importance of GalNAc-type O-glycosylation in EPH receptor-regulated diseases and identifies C1GALT1 as a potential therapeutic target for gastric cancer.

Comprehensive immune profiling and immune-monitoring using body fluid of patients with metastatic gastric cancer

Background

The aim of this study is to profile the cytokines and immune cells of body fluid from metastatic gastric cancer (mGC), and evaluate the potential role as a prognostic factor and the feasibility as a predictive biomarker or monitoring source for immune checkpoint inhibitor.

Methods

Body fluid including ascites and pleural fluid were obtained from 55 mGC patients and 24 matched blood. VEGF-A, IL-10, and TGF-β1 were measured and immune cells were profiled by fluorescence assisted cell sorting (FACS).

Results

VEGF-A and IL-10 were significantly higher in body fluid than in plasma of mGC. Proportion of T lymphocytes with CD69 or PD-1, memory T cell marked with CD45RO, and number of Foxp3+ T regulatory cells (Tregs) were significantly higher in body fluid than those in blood of mGC. Proportion of CD8 T lymphocyte with memory marker (CD45RO) and activation marker (HLA-DR), CD3 T lymphocyte with PD-1, and number of FoxP3+ Tregs were identified as independent prognostic factors. When patients were classified by molecular subgroups of primary tumor, VEGF-A was significantly higher in genomically stable (GS)-like group than that in chromosomal instability (CIN)-like group while PD-L1 positive tumor cells (%) showed opposite results. Monitoring immune dynamics using body fluid was also feasible. Early activated T cell marked with CD25 was significantly increased in chemotherapy treated group.

Conclusions

By analyzing cytokines and proportion of immune cells in body fluid, prognosis of patients with mGC can be predicted. Immune monitoring using body fluid may provide more effective treatment for patients with mGC.

Electronic supplementary material

The online version of this article (10.1186/s40425-019-0708-8) contains supplementary material, which is available to authorized users.

A Case of Advanced Gastric Cancer with Peritoneal Metastasis Treated Successfully with Nivolumab

Peritoneal metastasis (PM) is detected in 14% of gastric cancers at the time of initial diagnosis, with a median survival time of 4 months. A 66-year-old woman diagnosed with cT4a(SE) N2M1(LYN) cStage IV was treated with three lines of chemotherapy for a year. During the third line of chemotherapy, computed tomography (CT) scan revealed a large amount of ascites, periportal collar sign, and bilateral ureteral stenosis owing to PM. The tumor biomarkers (CEA and CA 19-9) remained elevated similar to the initial levels. The patient was administered 3 mg/kg nivolumab intravenously biweekly as the fourth line of chemotherapy. Three months after the nivolumab treatment, gastroscopy revealed an extreme reduction of the tumor size, while CT scan revealed the absence of ascites and a well-controlled tumor. There was no immune-related adverse event with nivolumab during and after the treatment, and performance status improved to 0. The patient has been alive for about 2.5 years since her first visit with her sixth line of chemotherapy (docetaxel). We report a case of advanced gastric cancer with PM that was treated successfully with nivolumab.

Survival Benefit of Neoadjuvant Chemotherapy with S-1 Plus Docetaxel for Locally Advanced Gastric Cancer: A Propensity Score-Matched Analysis

Background

Postoperative docetaxel plus S-1 (DS) chemotherapy is expected to be the standard therapeutic strategy for pStage III gastric cancer based on the results of the JACCRO GC-07 study. Neoadjuvant chemotherapy (NAC) is thought to have several advantages over adjuvant settings.

Objective

This study aimed to compare the efficacies of NAC DS and the surgery-first strategy for advanced gastric cancer patients with D2 gastrectomy.

Methods

This was a retrospective, single-institution observational study. Of 171 patients with locally advanced (cStage IIB or III) gastric cancer who underwent curative D2 gastrectomy and received NAC DS and/or S-1 adjuvant chemotherapy between 2011 and 2017, 76 (after propensity score matching for 132 patients who met the eligibility criteria) were enrolled in this study. The 3-year progression-free survival (PFS) rate was used to directly compare efficacies between NAC DS patients and surgery-first patients.

Results

The 3-year PFS rates for the NAC DS group were significantly higher than those for the surgery-first group (80.0 vs. 58.7; p = 0.037), and the progression hazard ratio of the NAC DS group compared with the surgery-first group was 0.394 (95% confidence interval 0.159–0.978; p = 0.045).

Conclusions

The NAC DS group showed a high 3-year PFS compared with the surgery-first group, with standard S-1 postoperative chemotherapy or observation. NAC DS can be expected to be beneficial as the standard therapy for advanced gastric cancer and should be adopted for the test arm of a randomized controlled phase III trial.

Electronic supplementary material

The online version of this article (10.1245/s10434-019-07299-7) contains supplementary material, which is available to authorized users.

Formalin fixation on HER-2 and PD-L1 expression in gastric cancer: A pilot analysis using the same surgical specimens with different fixation times

BACKGROUND

The needs for human epidermal growth factor receptor 2 (HER-2) and/or programmed death-ligand 1 (PD-L1) evaluations in gastric cancer are dramatically increasing. Although the importance of standardization of sample fixation has been widely recognized, most of the evidence regarding the fixation duration or type of fixing solution are based on breast cancer.

AIM

To investigate the real effects of fixation conditions on HER-2 testing or PD-L1 testing for gastric cancer using gastrectomy specimens.

METHODS

Thirty-two patients who underwent gastrectomy for gastric cancer were enrolled. Their resected specimens were each divided into four pieces and fixed in four strictly controlled different durations (6 h, 24 h, and 48 h, and 1 wk) by 10% formalin (n = 22) or 10% neutral buffered formalin (NBF) (n = 10). Immunohistochemistry (IHC) of HER-2 and PD-1 was performed, and a pathology examination was conducted. In the HER-2-immunoreactive cases, all four specimens were subjected to dual-color in situ hybridization (DISH). Five cases were assessed as HER-2-positive by IHC and DISH. We used the cut-off values of 1%, 10%, and 50% to assess the IHC findings of PD-L1.

RESULTS

No significant difference was observed in comparisons between the shorter fixation period groups (6 h, 24 h, and 48 h) and the prolonged fixation period (1 wk) group in the HER-2 and PD-L1 analyses. Although no significant difference was observed between 10% formalin and 10% NBF within 1 wk of fixation, the superiority of 10% NBF was confirmed in a long-term (> 3 mo) fixation in both the HER-2 and PD-L1 analyses.

CONCLUSION

In this small-numbered pilot study, prolonged fixation within 1 wk showed no inferiority in HER-2 or PD-L1 testing. However, a large-numbered prospective study is needed to obtain conclusive results.

Molecular features and translational outlook for Epstein-Barr virus-associated gastric cancer

Epstein-Barr Virus (EBV) was the first discovered human tumor virus and is the etiological agent of B cell lymphomas and also epithelial cancers. Indeed, nearly 10% of gastric cancers worldwide are EBV-positive and display unique molecular, epigenetic, and clinicopathological features. EBV-positive gastric cancers display the highest rate of host genome methylation of all tumor types studied and harbor recurrent mutations activating PI3Kα, silencing ARID1A, and amplifying PD-L1. While EBV infection of B cells can be studied efficiently, de novo epithelial cell infection is much more difficult. We propose that new culture models including 3D-based gastric organoids and xenografts can bring new insight into EBV-induced gastric carcinogenesis and will lead to improved precision medicine-based therapies for patients with EBV-positive gastric cancer.

Efficacy and safety of trastuzumab as maintenance or palliative therapy in advanced HER2-positive gastric cancer

BACKGROUND

Human epidermal growth factor receptor 2 (HER2)-positive gastric cancer (GC) is a unique subtype of this disease. Few studies focus on the feasibility of trastuzumab as maintenance or palliative therapy for patients with HER2-positive advanced GC.

PATIENTS AND METHODS

We retrospectively analyzed the data of 11 patients, evaluated the efficacy and safety of trastuzumab, and attempted to investigate the prognostic factors for trastuzumab treatment. Among the 11 patients, one achieved partial response (PR), six achieved stable disease (SD), and four were evaluated as progressive disease (PD).

RESULTS

The overall response rate (ORR) was 9.10%, and the disease control rate (DCR) was 63.64%. The median overall survival (OS) was 6.10 months, and the median progression-free survival (PFS) was 6.10 months. A significant association was found between trastuzumab treatment cycles and efficacy (P=0.027), cycles and PFS (P=0.001), and cycles and OS (P=0.005). Among the five patients who accepted more than five cycles of trastuzumab, the median OS and median PFS achieved 23.83 months and 14.67 months, respectively. Moreover, we have found the correlation between tumor marker changes and efficacy (P=0.002) and HER2 status and PFS (P=0.027). No association was found between HER2 status and OS (P=0.597).

CONCLUSION

The most common adverse events were left ventricular ejection fraction (LVEF) reduction, fatigue, and anorexia. LVEF reduction was found in seven of 11 patients, but the absolute decline in the LVEF was within 10% from the baseline. The results of this study suggest that trastuzumab is a feasible option as maintenance or palliative therapy for patients with HER2-positive metastatic GC.

Emerging Therapies in the Management of Advanced-Stage Gastric Cancer

Globally, gastric malignancy contributes to significant cancer-related morbidity and mortality. Despite a recent approval of two targeted agents, trastuzumab and ramucirumab, the treatment options for advanced-stage gastric cancer are limited. Consequently, the overall clinical outcomes for patients with advanced-stage gastric cancer remain poor. Numerous agents that are active against novel targets have been evaluated in the course of randomized trials; however, most have produced disappointing results because of the molecular heterogeneity of gastric cancer. The Cancer Genome Atlas (TCGA) project proposed a new classification system for gastric cancer that includes four different tumor subtypes based on molecular characteristics. This change led to the identification of several distinct and potentially targetable pathways. However, most agents targeting these pathways do not elicit any meaningful clinical benefit when employed for the treatment of advanced-stage gastric cancer. Most advanced-stage gastric cancer trials currently focus on agents that modulate tumor microenvironments and cancer cell stemness. In this review, we summarize data regarding novel compounds that have shown efficacy in early phase studies and show promise as effective therapeutic agents, with special emphasis on those for which phase III trials are either planned or underway.

Prognostic significance of tumor immune microenvironment and immunotherapy: Novel insights and future perspectives in gastric cancer

Despite a decrease in gastric cancer incidence, the development of novel biologic agents and combined therapeutic strategies, the prognosis of gastric cancer remains poor. Recently, the introduction of modern immunotherapy, especially using immune checkpoint inhibitors, led to an improved prognosis in many cancers. The use of immunotherapy was also associated with manageable adverse event profiles and promising results in the treatment of patients with gastric cancer, especially in heavily pretreated patients. These data have led to an accelerated approval of some checkpoint inhibitors in this setting. Understanding the complex relationship between the host immune microenvironment and tumor and the immune escape phenomenon leading to cancer occurrence and progression will subsequently lead to the identification of prognostic immune markers. Furthermore, this understanding will result in the discovery of both new mechanisms for blocking tumor immunosuppressive signals and pathways to stimulate the local immune response by targeting and modulating different subsets of immune cells. Due to the molecular heterogeneity of gastric cancers associated with different clinico-biologic parameters, immune markers expression and prognosis, novel immunotherapy algorithms should be personalized and addressed to selected subsets of gastric tumors, which have been proven to elicit the best clinical responses. Future perspectives in the treatment of gastric cancer include tailored dual immunotherapies or a combination of immunotherapy with other targeted agents with synergistic antitumor effects.

Molecular biomarkers in gastro-esophageal cancer: recent developments, current trends and future directions

Gastro-esophageal adenocarcinomas (GEA) represent a severe global health burden and despite improvements in the multimodality treatment of these malignancies the prognosis of patients remains poor. HER2 overexpression/amplification has been the first predictive biomarker approved in clinical practice to guide patient selection for targeted treatment with trastuzumab in advanced gastric and gastro-esophageal junction cancers. More recently, immunotherapy has been approved for the treatment of GEA and PD-L1 expression is now a biomarker required for the administration of pembrolizumab in these diseases. Significant progress has been made in recent years in dissecting the genomic makeup of GEA in order to identify distinct molecular subtypes linked to distinct patterns of molecular alterations. GEA have been found to be highly heterogeneous malignances, representing a challenge for biomarkers discovery and targeted treatment development. The current review focuses on an overview of established and novel promising biomarkers in GEA, covering recent molecular classifications from TCGA and ACRG. Main elements of molecular heterogeneity are discussed, as well as emerging mechanisms of primary and secondary resistance to HER2 targeted treatment and recent biomarker-driven trials. Future perspectives on the role of epigenetics, miRNA/lncRNA and liquid biopsy, and patient-derived xenograft models as a new platform for molecular-targeted drug discovery in GEA are presented. Our knowledge on the genomic landscape of GEA continues to evolve, uncovering the high heterogeneity and deep complexity of these tumors. The availability of new technologies and the identification of promising novel biomarker will be critical to optimize targeted treatment development in a setting where therapeutic options are currently lacking. Nevertheless, clinical validation of novel biomarkers and treatment strategies still represents an issue.

Successful treatment of liver metastases arising from early gastric cancer achieved clinical complete response by nivolumab

BACKGROUND

Although a recent randomized clinical trial has demonstrated that the objective response rate to nivolumab for metastatic gastric cancer was 11.2%, there was no patients confirmed complete response. Herein, we report on a case of liver metastasis arising from early gastric cancer in which a complete clinical response was achieved to nivolumab as third-line therapy.

CASE PRESENTATION

A 77-year-old man was referred to Kochi Medical School Hospital for the treatment of liver metastases from gastric cancer. The patient had undergone laparoscopic total gastrectomy with regional lymph node dissection 30 months prior for early gastric cancer, with a final diagnosis of T1N0M0, stage IA. The patient developed solitary splenic metastasis measuring 42 mm 28 months later and underwent splenectomy because there was no evidence of further metastatic lesions in any other organ. The patient was treated with S-1 plus oxaliplatin based on negative immunohistochemical staining of the resected specimens for human epidermal growth factor receptor 2 (HER2). Four months after the splenectomy, the patient developed multiple liver metastases and was treated with ramucirumab plus paclitaxel. Because of disease progression, the patient was administered 3 mg/kg, i.v., nivolumab every 2 weeks. After 4 cycles of systemic treatment using nivolumab, abdominal computed tomography revealed marked shrinkage of the liver metastases. After 12 cycles of nivolumab, the liver metastases had disappeared completely. The patient did not develop any adverse reactions, including immune-reactive adverse events, during treatment. The patient continues to receive nivolumab, and there is no evidence of disease recurrence in the 8-month period since starting nivolumab.

CONCLUSIONS

To the best of our knowledge, this is the first case report in the English literature of a gastric cancer patient achieving a complete clinical response to nivolumab, and highlights the potential for successful treatment of metastatic gastric cancer using nivolumab.

Immunotherapy for Gastric Cancer: Time for a Personalized Approach?

Over the last decade, our understanding of the mechanisms underlying immune modulation has greatly improved, allowing for the development of multiple therapeutic approaches that are revolutionizing the treatment of cancer. Immunotherapy for gastric cancer (GC) is still in the early phases but is rapidly evolving. Recently, multi-platform molecular analyses of GC have proposed a new classification of this heterogeneous group of tumors, highlighting subset-specific features that may more reliably inform therapeutic choices, including the use of new immunotherapeutic drugs. The clinical benefit and improved survival observed in GC patients treated with immunotherapeutic strategies and their combination with conventional therapies highlighted the importance of the immune environment surrounding the tumor. A thorough investigation of the tumor microenvironment and the complex and dynamic interaction between immune cells and tumor cells is a fundamental requirement for the rational design of novel and more effective immunotherapeutic approaches. This review summarizes the pre-clinical and clinical results obtained so far with immunomodulatory and immunotherapeutic treatments for GC and discusses the novel combination strategies that are being investigated to improve the personalization and efficacy of GC immunotherapy.

Blockade of ITGA2 Induces Apoptosis and Inhibits Cell Migration in Gastric Cancer

Background

Gastric cancer is currently the fourth leading cause of cancer-related death worldwide. Gastric cancer is often diagnosed at advanced stages and the outcome of the treatment is often poor. Therefore, identifying new therapeutic targets for this cancer is urgently needed. Integrin alpha 2 (ITGA2) subunit and the beta 1 subunit form a heterodimer for a transmembrane receptor for extracellular matrix, is an important molecule involved in tumor cell proliferation, survival and migration. Integrin α2β1 is over-expressed on a variety of cancer cells, but is low or absent in most normal organs and resting endothelial cells.

Results

In this report, we assessed the ITGA2 as the potential therapeutic target with the bioinformatics tools from the TCGA dataset in which composed of 375 gastric cancer tissues and 32 gastric normal tissues. According to the information from the Cancer Cell Line Encyclopedia (CCLE) database, the AGS cell line with ITGA2 high expression and the SUN-1 cell line with low expression were chosen for the further investigation. Interestingly, the anti-ITGA2 antibody (at 3 μg/ml) inhibited approximately 50% survival of the AGS cells (over-expressed ITGA2), but had no effect in SNU-1 cells (ITGA2 negative). The extents of antibody-mediated cancer inhibition positively correlated with the expression levels of the ITGA2. We further showed that the anti-ITGA2 antibody induced apoptosis by up-regulating the RhoA-p38 MAPK signaling to promote the expressions of Bim, Apaf-1 and Caspase-9, whereas the expressions of Ras and Bax/Bcl-2 were not affected. Moreover, blocking ITGA2 by the specific antibody at lower doses also inhibited cell migration of gastric cancer cells. Blockade of ITGA2 by a specific antibody down-regulated the expression of N-WASP, PAK and LIMK to impede actin organization and cell migration of gastric cancer cells.

Conclusions

Here, we showed that the mRNA expression levels of ITGA2 comparing to normal tissues significantly increased. In addition, the results revealed that targeting integrin alpha 2 subunit by antibodies did not only inhibit cell migration, but also induce apoptosis effect on gastric cancer cells. Interestingly, higher expression level of ITGA2 led to significant effects on apoptosis progression during anti-ITGA2 antibody treatment, which indicated that ITGA2 expression levels directly correlate with their functionality. Our findings suggest that ITGA2 is a potential therapeutic target for gastric cancer.

Pembrolizumab for treatment of advanced gastric and gastroesophageal junction adenocarcinoma

Pembrolizumab is a monoclonal antibody directed against PD-1 that is US FDA approved for treatment of advanced PD-L1 positive gastric and gastroesophageal junction adenocarcinoma in patients who have progressed on at least two prior lines of chemotherapy. This article summarizes the clinical evidence regarding safety, tolerability and efficacy of pembrolizumab in this setting. In addition, this article describes the investigational use of pembrolizumab as first- and second-line therapy and in combination with other treatments. Finally, this review compares other checkpoint inhibitors to pembrolizumab for the treatment of this disease, and explores predictive biomarkers of response to PD-1 blockade.